1. Field of the Invention
The present invention relates to an inlet diffuser for an oil separator assembly. In particular, the present invention is directed to a cone inlet diffuser capable of removing oil entrained in a compressed refrigerant gas as the gas and entrained oil pass through the inlet diffuser.
2. Description of the Prior Art
Refrigeration and liquid chilling systems typically operate under a closed loop design, such that refrigerant is continuously recirculated through the liquid chilling system. Generally, the components of a refrigeration or liquid chilling system include a compressor for compressing and circulating refrigerant gas, a condenser for cooling and condensing the compressed refrigerant gas into a refrigerant liquid, and an evaporator for absorbing surrounding heat and evaporating the refrigerant liquid into refrigerant gas for subsequent compression and recirculation.
To lubricate and seal the internal mechanisms of the compressor, oil is typically injected into the compressor with the refrigerant gas. In operation, some of the oil atomizes and becomes entrained in the compressed refrigerant gas. This entrainment of oil in the circulating refrigerant gas can prove detrimental to the chilling system for at least two reasons.
First, oil must constantly be available in the compressor to lubricate and seal the internal mechanisms and assist in cooling the refrigerant gas undergoing compression. Upon entrainment, however, the oil is typically displaced from the compressor as it circulates through the system with the refrigerant gas. The oil is then likely to become trapped in a system component located downstream from the compressor, such as the condenser or evaporator. Since a lubricant and sealant must be maintained in the compressor, either additional oil must be introduced into the compressor, which would inevitably lead to oversaturation of the refrigerant gas with oil, or return lines must be provided to remove the trapped oil from the downstream components and reintroduce it into the compressor.
Second, the entrainment of oil in the circulating refrigerant gas may severely impair both the operation of the chilling system and the efficiency of the refrigerant gas. As the refrigerant gas entrained with oil is circulated through the chilling system, the oil tends to coat the heat exchanging surfaces of the condenser and evaporator. This results in a loss in the thermal efficiency of these heat exchangers. Likewise, the entrainment of oil may also reduce the cooling characteristics of the refrigerant gas and liquid, itself.
Hence, it is imperative that such a liquid chilling system include an oil separator downstream from the compressor to remove and collect oil entrained in the circulating refrigerant gas and reintroduce the collected oil into the compressor. The need for oil separators in refrigeration and liquid chilling systems is well recognized, particularly with the advent of screw compressors. A significant quantity of oil is typically required to properly seal and lubricate the internal mechanisms of a screw compressor. Further, since screw compressors may have capacities in excess of 600 ton, the oil separator utilized in combination with a screw compressor must be extremely durable to withstand the forces associated with such a large operating capacity.
A variety of oil separator assemblies have been developed to separate oil from a flowing gas. Examples of previously designed systems are disclosed in U.S. Pat. Nos. 2,074,323 to Borgerd; No. 3,283,532 to Kocher; No. 3,563,053 to Bottum; No. 4,472,949 to Fujisawa et al.; No. 4,622,048 to Roberts et al.; and No. 4,906,264 to Szymaszek et al. These previous attempts to separate oil from a gaseous flow base included concentric funnel assemblies (Borgerd); a combination of filters and baffles (Kocher); and devices utilizing centrifugal force to achieve the separation (Bottum, Fujisawa et al., Roberts et al., and Szymaszek et al.). In the Applicants' view, each of these proposed oil separator assemblies present disadvantages. More specifically, the Applicants believe that in commercial application these proposed oil separator assemblies are not successful at separating oil from gas to the degree such separation is desired, particularly in the refrigeration field.